WO2001050636A1 - Cellular telephone - Google Patents

Abstract

A dual-mode cellular telephone of diversity reception for W-CDMA and PDC systems comprises a transmitting and receiving antenna (1), a receiving antenna (2), a W-CDMA transmitter circuit (11), a W-CDMA receiver circuit (12), PDC transmitter circuit (13), a PDC receiver circuit (14), switches (SW1-SW3) for selective connection between the antennas (1, 2) and the W-CDMA circuits (11, 12) or the PDC circuits (13, 14), and a band separator (3).

Description

 Specification

Mobile phone technology

 The present invention relates to a mobile phone, and more particularly, to a diversity mobile phone that can be used in both a continuous transmission / reception system for continuously transmitting and receiving signals and a time-division transmission / reception system for transmitting and receiving signals in a time-division manner. is there. Background art

 2. Description of the Related Art Conventionally, a cellular phone has adopted a PDC scheme, which is a type of a TDMA scheme that performs time-division transmission and reception of signals. In addition, a diversity system has been adopted in which a mobile phone is provided with two antennas and the received data is reproduced based on the levels of signals received by the two antennas.

 On the other hand, it is planned to shift the mobile phone system from the above-mentioned PDC system to a W-CDMA system which continuously transmits and receives signals. In this transition period, it is expected that there will be a period in which both PDC and W-CDMA systems will coexist, and there is also a need for dual-mode handsets that can be used in both systems. However, simply combining two PDC and W—CDMA mobile phones into one dual-mode mobile phone would increase the device dimensions. In particular, if a diversity system is to be realized in each system, four antennas will be required, and the size of the equipment will increase. Disclosure of the invention

 The present invention provides a mobile phone that can be used in both a continuous transmission / reception system and a time division transmission / reception system, can realize a diversity system in each system, and can reduce the size of the device. It is intended to do so.

An object of the present invention is to provide a diver that can be used in both a continuous transmission / reception system for continuously transmitting and receiving signals and a time division transmission / reception system for transmitting and receiving signals in a time-division manner. A mobile phone of a mobile communication system, comprising first and second antennas provided apart from each other, a first transmitting / receiving circuit for transmitting / receiving a signal to / from a base station of a continuous transmitting / receiving system, and a time-division transmitting / receiving system. A second transmission / reception circuit for transmitting / receiving signals to / from the base station, and a second transmission / reception system based on the reception signals of the first and second transmission / reception circuits. When the main circuit operates to transmit / receive a signal to / from the base station of the main system, the judgment circuit determines whether the main system is the main system and the other is the monitor system. When the corresponding first or second transmission / reception circuit is coupled to the first and second antennas and a signal is received from the base station of the monitor system, when the monitor system receives the signal from the monitor system, This is achieved by providing a mobile phone including a corresponding first or second transmission / reception circuit and a coupler that couples the first and second antennas.

 The main advantage of the present invention is that it can be used in both a continuous transmission / reception system and a time division transmission / reception system, a diversity system can be realized in each system, and two antennas are shared by two systems. This is because the size can be reduced.

 Preferably, the coupler is provided between the first antenna and the first transmission / reception circuit, and includes a first filter that passes only a signal of the continuous transmission / reception system, and a second antenna and the second transmission / reception circuit. And a second filter that passes only the signal of the time-division transmitting / receiving system, and a second antenna and the first transmitting / receiving circuit when the first transmitting / receiving circuit is used. When a transmitting / receiving circuit is used, it includes a switching circuit that couples the first antenna and the second transmitting / receiving circuit via the second filter and couples the second antenna and the second transmitting / receiving circuit. In this case, the first antenna used for signal transmission and reception and the first and second transmission / reception circuits are coupled by a filter, so that signal power loss during transmission can be suppressed. Also, since the switching circuit can be made into an IC, the size of the device can be reduced.

Also preferably, the coupler is provided between the first antenna and the first transmission / reception circuit, the first filter passing only a signal of the continuous transmission / reception system, and the first filter. A second filter provided between the antenna and the second transmission / reception circuit and passing only the signal of the time division transmission / reception system, and supplied to the first input / output port via the first antenna and the second filter. The received signal is supplied to the second transmitting / receiving circuit via the second input / output port, and the transmitting signal supplied from the second transmitting / receiving circuit to the third input / output port is supplied to the first input / output port and the second input / output port. When the first transmitting / receiving circuit is used, the circulator provided to the first antenna via the filter and the second antenna and the first transmitting / receiving circuit are combined, and the second transmitting / receiving circuit is used. In the case, a switching circuit for coupling the second antenna and the second transmitting / receiving circuit is included. In this case, the use of the circuit illuminator can simplify the control of the switching circuit.

 Also preferably, the coupler is provided between the first and second antennas and the first transmitting and receiving circuit, respectively, and the first and second filters pass only signals of the continuous transmitting and receiving system, A third filter and a fourth filter are provided between the first and second antennas and the second transmitting and receiving circuit, respectively, and pass only signals of the time division transmitting and receiving system, and the first antenna and the third filter. A reception signal provided to the first input / output port via the second input / output port is provided to the second transmission / reception circuit via the second input / output port, and a transmission signal provided to the third input / output port from the second transmission / reception circuit is provided. A circulator for providing a signal to the first antenna via the first input / output port and the third filter. In this case, since the first to fourth filters and the circulator are used, the power loss can be reduced, and the control of the coupler becomes unnecessary.

Also preferably, the coupler is provided between the first and second antennas and the first transmitting and receiving circuit, respectively, and the first and second filters pass only signals of the continuous transmitting and receiving system, Third and fourth filters are provided between the first and second antennas and the second transmitting and receiving circuit, respectively, and pass only signals of the time division transmitting and receiving system. The transmission signal output from the second transmission / reception circuit is supplied to the first antenna via the third filter, and when the second transmission / reception circuit receives the signal, the reception signal of the first antenna is transmitted through the third filter. And a switching circuit provided to the second transmission / reception circuit. In this case, since the first to fourth filters and the switching circuit are used, power loss can be reduced, and the size of the device can be reduced. Also preferably, the first transmission / reception circuit generates reception data based on the reception signals from the first and second antennas, and the second transmission / reception circuit generates the reception data from the first and second antennas. The signal with the higher signal level is selected, and the receiving data is generated based on the selected received signal. In this case, the signals received from the first and second antennas are combined or a signal having a higher signal level is selected, so that the signal can be received with high sensitivity. BRIEF DESCRIPTION OF THE FIGURES

 FIG. 1 is a circuit block diagram showing a main part of a dual mode mobile phone according to an embodiment of the present invention,

 FIG. 2 is a frequency spectrum diagram of signals of the W_CDMA system and the PCD system used in the dual mode mobile phone shown in FIG. 1,

 FIG. 3 is a diagram for explaining the operation of the dual-mode mobile phone shown in FIG. 1,

 FIG. 4 is a time chart for explaining the operation of the dual mode mobile phone shown in FIG. 1,

 FIG. 5 is another time chart for explaining the operation of the dual mode mobile phone shown in FIG. 1,

 FIG. 6 is a circuit block diagram showing a modification of this embodiment,

 FIG. 7 is a diagram for explaining the operation of the dual mode mobile phone shown in FIG. 6,

 FIG. 8 is a circuit block diagram showing another modification of this embodiment,

 FIG. 9 is a diagram for explaining the operation of the dual mode mobile phone shown in FIG. 8,

FIG. 10 is a circuit block diagram showing still another modification of this embodiment, and FIG. 11 is a diagram for explaining the operation of the dual mode mobile phone shown in FIG. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a dual mode mobile phone according to the present invention will be described in detail with reference to the drawings. Referring to FIG. 1, this dual-mode mobile phone has a transmitting / receiving antenna 1, a receiving antenna 2, band demultiplexers 3, 6, switches SW1 to SW3, W—CDMA transmitting circuit 11, W—CDMA receiving circuit 1 2, PDC transmission circuit 13, PDC reception circuit 14, and control circuit 15 are provided.

 The transmitting / receiving antenna 1 is used for transmitting / receiving both W-CDMA and PDC signals. As shown in FIG. 2, the transmission signal Tx1 and the reception signal Rx1 of the W-CDMA system have a frequency of about 2 GHz, and the transmission signal Tx2 and the reception signal Rx2 of the PDC system are 0.8. It has a frequency of about GH z. In order to transmit and receive such two types of signals having different frequencies, the transmitting and receiving antenna 1 is configured to have two resonance points. The receiving antenna 2 also has two resonance points and is used for receiving both W-CDMA and PDC signals. The space diversity system is realized by the two antennas 1 and 2.

 The band splitter 3 includes a high-pass filter (HPF) 4, a low-pass filter (LPF) 5, and three input / output ports 3a to 5a. Port 3 a is connected to transmitting / receiving antenna 1. W— CDMA signals TX 1 and Rxl can pass through the path of port 3 a, noise pass filter 4 and port 4 a, and PDC signals T x 2 and R x 2 correspond to port 3 a It can pass through the path of the low-pass filter 5 and the port 5a.

 Band splitter 6 includes two band pass filters (BPF) 7, 8 and three ports 6a to 8a. Ports 6 a to 8 a are respectively connected to port 4 a of band demultiplexer 3, W—output terminal 11 a of DCMA transmitting circuit 11, and W—C DMA receiving circuit 12 1st input terminal 12 a Connected to. The W-CDMA transmission signal TX 1 (1920 to 1998 OMHz) can pass through the path of port 7a, bandpass filter 7 and port 6a, and the W_CDMA reception signal Rx 1 (2 11 0 to 21 7 OMHz) can pass through the path of port 6a, the non-pass filter 8, and the port 8a.

The common terminal T3a of the switch SW1 is connected to the receiving antenna 2, the first switching terminal T1a is connected to the second switching terminal T2c of the switch SW3, and the second switching terminal The child T 2 a is connected to the second input terminal 12 b of the W—CDMA receiving circuit 12. The switch SW1 is switch-controlled by the control circuit 15. The state where the terminals T la and T3 a are conducting is state “1”, and the state where the terminals T2 a and T3 a are conducting is state “2”.

 The common terminal T3b of the switch SW2 is connected to the port 5a of the band splitter 3, and its first switching terminal T1b is connected to the output terminal 13a of the PDC transmission circuit 13 and its second terminal The switching terminal T2b is connected to the first switching terminal T1c of the switch SW3. The switching of the switch SW2 is controlled by the control circuit 15. The state where the terminals Tlb and T3b are conducting is state “1”, and the state where the terminals T2c and T3c are conducting is state “2”.

 The W-CDMA transmission circuit 11 is activated when the W-CDMA system is the main system, and generates a transmission signal T X1 according to the transmission data generated based on the voice of the user of the mobile phone. Transmission signal T X1 is applied to transmission / reception antenna 1 via band-pass filter Ί and high-pass filter 4.

 When the W—C DMA system is the main system, the W—CDMA reception circuit 12 receives the signal Rx 1 received by the transmission / reception antenna 1 and given through the high-pass filter 4 and the band-pass filter 8, The signal Rx \ 'received by the receiving antenna 2 and given via the switch SW1 is combined to generate received data. The received data is converted into voice and transmitted to the user of the mobile phone.

 The W-CDMA receiving circuit 12 monitors information from the base station of the W-CDMA system based on the received signals Rxl and Rx1 'when monitoring when the PDC system is the main system. The reason for monitoring the information of the base station in the W-CDMA system in this way is to promptly transition to the W-CDMA system when the signal level from the base station in the PDC system decreases.

 The PDC transmission circuit 13 is activated when the PDC system is the main system, and generates a transmission signal Tx2 according to the transmission data. The transmission signal # 2 is provided to the transmission / reception antenna 1 via the switch SW2 and the low-pass filter 5.

The PDC receiving circuit 14 is a main circuit when the PDC system is the main system. During operation of the system, the signal Rx 2 received by the transmitting / receiving antenna 1 and applied through the low-pass filter 5 and the switches SW2 and SW3 or the signal Rx 2 received by the receiving antenna 2 and applied through the switches SW1 and SW3 Based on the received speech data.

 Further, the PDC receiving circuit 14 monitors information from the base station of the PDC system based on the signal Rx2 when monitoring when the W-CDMA system is the main system. The reason for monitoring the information from the base station in the PDC system in this way is to quickly transition to the PDC system when the signal from the base station in the W-CDMA system becomes weak.

 The control circuit 15 performs W-CDMA and P based on signals from the reception circuits 12 and 14.

It determines which of the DC systems has a higher signal level, the system with the higher signal level is the main system, and the system with the lower signal level is the monitor system. The control circuit 15 controls the switches SW1 to SW3, the transmission circuits 11, 13 and the reception circuits 12, 14 based on the determination result.

 FIG. 3 is a diagram showing the states of the switches SW :! to SW3 shown in FIG. The operation of the mobile phone will be described below with reference to FIG.

 First, the control circuit 15 compares the signal levels of the received signal Rx1 of the W—CDMA system and the received signal Rx2 of the PDC system, and the system with the higher signal level is used as the main system, and the signal level with the lower signal level is used. Is the monitor system.

When the W—C DMA system is the main system and the telephone is in a talk state, when the main system is operating, switch SW1 is in state “2” and terminals T2a and T3a conduct, and SW2 and SW3 are connected. Are in DZC (Don't Care) state. The signal Rx 1 received by the antenna 1 is input to the first input terminal 12a of the W-CDMA receiving circuit 12 via the high-pass filter 4 and the band-pass filter 8, and is also received by the antenna 2. The signal Rx 1 ′ is input to the second input terminal 12 b of the W—C DMA receiving circuit 12 via the switch SW 1. The W-CDMA reception circuit 12 generates reception data based on signals Rxl and Rxl 'from the two antennas 1 and 2. That is, a space diversity system is realized. The signal Tx 1 generated by the W—CDMA transmission circuit 11 is supplied to the antenna 1 via the band-pass filter 6 and the high-pass filter 4, and further transmitted from the antenna 1 to the base station of the W—CDMA system. Is done. In this case, as shown in FIGS. 4 (a) and 4 (b), the transmission signal Tx1 is continuously transmitted, and the reception signals RX1 and Rx1 'are also continuously received. For this reason, the W-CDMA system is called a continuous transmission / reception system.

 When the W—C DMA system is the main system and the telephone is in a talking state, during monitoring, switch SW1 is in state “1”, terminals Tla and T3a conduct, and switch SW2 is in state “ 2 ”and the terminals T2 b and T 3 b conduct, and the switch SW2 receives the higher signal level of the signal RX 2 of the signal RX 2 received by the antenna 1 and the signal RX 2 received by the antenna 2 Becomes “1” or “2” so that is input to the PDC receiving circuit 14. In this case, as shown in FIGS. 4 (c) and (d), the output of the transmission signal Tx2 is stopped and the reception signal Rx2 is continuously received. The PDC receiving circuit monitors information from the base station of the PDC system based on the received signal Rx2.

 When the W-CDMA system is the main system and the phone is in the standby mode, the phone is the same as in the talk mode.

 When the PDC system is the main system and the telephone is in a talk state, when the main system is operating, switch SW1 is in state "1" and terminals Tla and T3a are conductive, and switch SW2 is transmitting and receiving. At this time, the state changes to `` 1 '' and `` 2 '' respectively, and switch SW3 sets the higher signal level of signal Rx2 of signal Rx2 received by antenna 1 and signal Rx2 received by antenna 2 to PDC The state changes to "1" or "2" as input to the receiving circuit 14. The signal Rx 2 with the higher signal level of the signal Rx 2 received by the antenna 1 and the signal Rx 2 received by the antenna 2 was input to the PDC receiving circuit 14, and the signal was input to the PDC receiving circuit 14. Generates reception data based on the signal Rx2. That is, a space diversity system is realized.

The signal Tx 2 generated by the P DC transmission circuit 13 is supplied to the antenna 1 via the switch SW 2 and the single-pass filter 5, Sent to the base station of the C system. In this case, reception of signal Rx 2 and transmission of signal Tx 2 are performed alternately in a time-division manner. That is, as shown in Fig. 5 (c) and (d), the signal Rx2 is received in the R (reception) slot, nothing is performed in the I (idle) slot, and the signal is transmitted in the T (transmission) slot. TX 2 is transmitted, the signal Rx 1 from antenna 1 is compared with the signal from antenna 2 in the LM (level measuring) slot, the state of switch SW3 is set, and signal Rx 2 is received in the R slot Is done. For this reason, the PDC system is called a time division transmission / reception system.

 When the PDC system is the main system and the telephone is in a talking state, when monitoring, switch SW1 is in state “2”, conduction is conducted between terminals T2a and T3a, and switches SW2 and SW3 are in DZC state. The W-CDMA receiving circuit 12 monitors information from the base station of the W-CDMA system based on the signals Rxl and RX1 'from the antennas 1 and 2.

 When the PDC system is the main system and the telephone is in the standby mode, it is basically the same as when the telephone is in the talking state. However, since transmission is not performed in the standby reception state, switch SW2 does not enter state “1”.

 In this embodiment, the two antennas 1 and 2 and the W-CDMA transmission circuit 11 and the reception circuit 12 or the two antennas 1 and 2 and the P-band splitter 3 and the switches SW1 to SW3 are used. The transmission circuit 13 and the reception circuit 14 of the DC system are selectively coupled. Therefore, it can be used in both W_CDMA and PDC systems, and in each system, a diversity system can be realized and the size of the equipment can be reduced.

 The reason why the transmitting / receiving antenna 1 and the W_CDMA transmitting circuit 11 are coupled by the filters 4 and 7 is to suppress the signal power loss during transmission. Also, since the switches SW1 to SW3 can be easily made into ICs, the size of the device can be reduced.

Hereinafter, a modified example of this embodiment will be described. In the modification shown in FIG. 6, the switch SW2 in FIG. 1 is replaced with a circulator 21. The circulator 21 includes three input / output ports 21a to 21c. The input / output ports 21a to 21c are respectively connected to the port 5a of the band splitter 3, the first switching terminal T1c of the switch SW3 and Connected to output node 13a of PDC transmission circuit 13. The signal Rx2 received by the antenna 1 and passed through the oral pass filter 5 and input to the port 21a is given to the first switching terminal T1c of the switch SW3 via the port 21b. The signal Tx2 generated in the PDC transmission circuit 13 and input to the port 21c is given to the input / output port 5a of the band splitter 3 via the port 21a. Therefore, the circuit regulator 21 plays the same role as the switch SW2. As shown in FIG. 7, the switches SW1 and SW3 are controlled to be switched in the same manner as described with reference to FIGS. In this modified example, control of the switch SW2 is not required, so that control is simplified.

 In the modification shown in FIG. 8, the switch SW1 in FIG. The band splitter 22 includes a low-pass filter 23, a high-pass filter 24, and three input / output ports 22a to 24a. The received signal Rx1 'of the W—CDMA system can pass through the path of the port 22a, the high-pass filter 24 and the port 24a, and the received signal Rx2 of the PDC system is the port 22a, It can pass through the path of the low-pass filter 23 and the port 23a. Therefore, the band splitter 22 plays the same role as the switch SW1. As shown in FIG. 9, the switching of the switch SW3 is controlled in the same manner as described with reference to FIGS. In this modified example, control of the switches SW1 and SW2 becomes unnecessary, so that control is simplified. In the modification shown in FIG. 10, the circulator 21 shown in FIG. 8 is replaced with a switch SW2. As shown in FIG. 11, the switches SW2 and SW3 are switched and controlled in the same manner as described with reference to FIG. 1 and FIG. In this modified example, control of the switch SW2 is not required, so that control can be simplified.

Claims

The scope of the claims  1. A diversity mobile phone that can be used in both a continuous transmission and reception system that continuously transmits and receives signals and a time-division transmission and reception system that performs time-division transmission and reception of signals.  First and second antennas (1, 2) spaced apart from each other,  A first transmitting / receiving circuit (6, 11, 12, 12) for transmitting / receiving a signal to / from the base station of the continuous transmitting / receiving system,  A second transmitting / receiving circuit (SW3, 13, 14) for transmitting / receiving a signal to / from the base station of the time division transmitting / receiving system,  One of the continuous transmission / reception system and the time division transmission / reception system is determined as a main system based on the reception signals of the first and second transmission / reception circuits (SW3, 6, 11 to 14), and the other is determined. Judgment circuit (15) for judging as a monitor system  During the operation of the main system, which transmits and receives signals to and from the base station of the main system, the first or second transmission / reception circuit (6, 1, 1, 12) corresponding to the system determined to be the main system by the determination circuit (15) is used. Alternatively, when the SW3, 13, 14) and the first and second antennas (1, 2) are coupled to each other and a signal is received from the base station of the monitor system, the monitoring is performed by the determination circuit (15). The first or second transmitting / receiving circuit (6, 11, 12, or SW3, 13, 14, 14) corresponding to the system determined to be a system is connected to the first and second antennas (1, 2). Equipped with couplers (4, 5, SW1, SW2, 21, 23, 24) 2. The coupler (4, 5, SW1, SW2)  The signal is provided between the first antenna (1) and the first transmission / reception circuit (6, 11, 12, 12), and passes a signal of the continuous transmission / reception system and blocks a signal of the time division transmission / reception system. The first filter (4), A second antenna provided between the first antenna (1) and the second transmission / reception circuit (SW3, 13, 14) for passing a signal of the time division transmission / reception system and blocking a signal of the continuous transmission / reception system; 2 filters (5), and When the main system is operating when the continuous transmission / reception system is the main system, and when monitoring when the time division transmission / reception system is the main system, the second antenna (2) and the first transmission / reception circuit (6, 11) , 12), and when the main system is operating when the time-division transmitting / receiving system is the main system and when monitoring when the continuous transmitting / receiving system is the main system, the second filter (5) is used. The first antenna (1) is coupled to the second transmission / reception circuit (SW3, 13, 14), and the second antenna (2) is coupled to the second transmission / reception circuit (SW3, 13, 14). The mobile phone according to claim 1, further comprising a switching circuit (SW1, SW2) that couples the mobile phone with the mobile phone.  3. The coupler (4, 5, 21, SW1)  The signal is provided between the first antenna (1) and the first transmission / reception circuit (6, 11, 12), and passes a signal of the continuous transmission / reception system and blocks a signal of the time division transmission / reception system. The first filter (4),  A second antenna that is provided between the first antenna (1) and the second transmission / reception circuit (SW3, 13, 14) and that passes a signal of the time division transmission / reception system and blocks a signal of the continuous transmission / reception system; 2 filters (5),  First to third input / output ports (3a to 5a), and the first input / output port (21a) via the first antenna (1) and the second filter (5). ) Is supplied to the second transmitting / receiving circuit (SW3, 13, 14) through the second input / output port (21b), and the second transmitting / receiving circuit (SW3, 13, 14) to transmit the transmission signal provided to the third input / output port (21c) via the first input / output port (21a) and the second filter (5) to the first antenna ( 1) to give to the circulatory collector (21), and At the time of main system operation when the continuous transmission / reception system is the main system, and at the time of monitoring when the time division transmission / reception system is the main system, the second antenna (2) and the first transmission / reception circuit (6, 1 1 and 12), and when the main system is operating when the time-division transmitting / receiving system is the main system, and when monitoring when the continuous transmitting / receiving system is the main system, the second antenna (2) is connected to the second antenna (2). The second transmission / reception circuit (SW3,13,1 4. The mobile phone according to claim 1, including a switching circuit (SW1) for coupling the mobile phone with the mobile phone. 4. The coupler (4, 5, 21, 23, 24)  The time-division transmission / reception system is provided between the first and second antennas (1, 2) and the first transmission / reception circuit (6, 11, 12, 12), and passes signals of the continuous transmission / reception system. First and second filters (4, 24) that block the signal of the system,  Each of the antennas is provided between the first and second antennas (1, 2) and the second transmission / reception circuit (SW3, 13, 14), and passes a signal of the time division transmission / reception system to transmit the signal of the continuous transmission / reception system. Third and fourth filters (5, 23) for blocking the signal, and  First to third input / output ports (21a to 21c), and the first input / output port (21a) via the first antenna (1) and the third filter (5). ) Is supplied to the second transmission / reception circuit (SW3, 13, 14) via the second input / output port (21b), and the second transmission / reception circuit (SW3, 13, 14) is supplied to the second transmission / reception circuit (SW3, 13, 14). ) To the third input / output port (21c) via the first input / output port (21a) and the third filter (5). The mobile phone according to claim 1, including a circulator (21) provided to 1). 5. The coupler (4, 5, 23, 24, SW2)  The time-division transmission / reception system is provided between the first and second antennas (1, 2) and the first transmission / reception circuit (6, 11, 12), and passes signals of the continuous transmission / reception system. First and second filters (4, 24) that block the signal of the system,  Each of the antennas is provided between the first and second antennas (1, 2) and the second transmission / reception circuit (SW3, 13, 14), and passes a signal of the time division transmission / reception system to transmit the signal of the continuous transmission / reception system. Third and fourth filters (5, 23) for blocking the signal, and When transmitting the second transmission / reception circuit (SW 3, 13, 14), the second transmission / reception circuit The transmission signal output from the circuit (SW3, 13 and 14) is supplied to the first antenna (1) via the third filter (5), and the second transmission and reception circuit (SW3, 13, and 14), the switching circuit (SW2) which supplies the received signal of the first antenna (1) to the second transmitting / receiving circuit (SW3, 13, 14) via the third filter (5). The mobile phone according to claim 1, comprising: 6. The first transmission / reception circuit (6, 11 1, 12) generates reception data based on the reception signals from the first and second antennas (1, 2),  The second transmission / reception circuit (SW3, 13, 14) selects a signal having a higher signal level among the reception signals from the first and second antennas (1, 2), and selects the selected signal. The portable telephone according to claim 1, wherein the receiving data is generated based on the received signal.